I've found over the years that my best way of dealing with heckles is either ignore it, especially if there is nothing you can do with it. If it is something you can use back, do so, but only if you have a good return. There's nothing worse than a limp reply from the performer. Or if the heckle is a good one just let it come and enjoy the laugh. After all you are the one up there and the audience are usually on your side. I had a memorable one thrown at me some time ago now.It was only in fun but also funny. I called out "Can you hear me at the back?" and the reply came " Yes, but I'm happy to swap places with someone who can't!"